Background:
Mouse studies at early stage of hypertrophic cardiomyopathy (HCM) indicate allele-specific differences in cardiac gene expression and mitochondrial function. But data at established disease stage in mouse and human HCM are lacking. We hypothesized that 1) allele-specific differences persist at established stage, and 2) mouse and human HCM have distinct molecular biosignatures.
Methods:
We analyzed the transcriptome (mRNA, miRNA) in 2 HCM
mouse
models (R92W-TnT, R403Q-MyHC)/littermate controls at 24weeks of age and in
human
myectomy samples/healthy-control hearts (
GSE36961, GSE36946
). We examined myocyte redox, mitochondrial DNA copy number (mtDNA-CN), respiration, ROSgeneration/scavenging and Ca
2+
handling in mutant/littermate-control
mice
.
Results:
Analysis of mRNA/miRNA expression and Ingenuity Pathway Analysis (IPA) revealed distinct allele-specific gene expression in mouse HCM and marked differences from human HCM. Only
CASQ1 and GPT1
were similarly regulated in both mouse HCM/human HCM. KEGG analysis revealed enrichment of several metabolic pathways, but only pyruvate metabolism was enriched in both mouse HCM/human HCM. IPA predicted upregulation of 2 pathways (inflammasome, type 2 diabetes signaling) in MyHC mutants, and upregulation of 18 pathways (including STAT3, ILK, Ca
2+
signaling) in TnT mutants; the anti-hypertrophic/anti-fibrotic LXR/RXR pathway was the most upregulated in human HCM. Losartan was a predicted therapy only in TnT mutants. Myocytes of both mutant mice exhibited an oxidized redox environment. Mitochondrial complex I respiration was lower in both mutants compared to controls. MyHC mutants had similar mtDNA-CN and mitochondrial Ca
2+
handling, but TnT mutants demonstrated lower mtDNA-CN and impaired mitochondrial Ca
2+
handling, compared to respective controls.
Conclusions:
Molecular profiling reveals allele-specific differences in mRNA/miRNA expression, intracellular signaling and mt-function/number in mouse HCM at established disease stage. Transcriptional differences between mouse and human HCM highlight the need for precision medicine approaches based on human studies.